Evaluation of denitrifying process in continuous with halotolerant consortium
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Abstract
Among the biological processes used for the treatment of effluent with nitrogen compounds, is the denitrifying process, which is highly selective for the removal of nitrate coupled to the oxidation of organic matter, including compounds know as recalcitrant, obtaining high percentages removal of substrates; additionally, coupled to the problem of discharges with high content of nitrogen compounds, are water-containig high concentrations of salts, therefore the aim of this work involves looking for microorganisms capable of carrying out the denitrifying continuous process in conditions of salinity. To achieve this, different microorganisms were isolated on selective medium, which were taken from sediments in the Bay of sea salt (San Ignacio Rio Muerto, Sonora). There were isolated 21 strains, which were characterized morphologically and biochemically, proving that some of them are capable of reducing nitrate.
To assess the ability of halotolerant microorganisms isolated to conducting denitrifying process, a upflow anaerobic sludge blanket (UASB) reactor under continuously denitrifying conditions was operated, fed with acetate, adjusting the nitrate in a stoichiometric ratio C/N of 1.1 with hydraulic residence time (HRT) of 2 d. The loading rate was 78.1 ± 9.4 mg C-acetate/l.d and 82.8 ± 6.8 mg N-NO3-/l.d showing the complete oxidation of acetate coupled to denitrification, consumption efficiencies obtained during the operation were 100% for the carbon compound and nitrate.
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